HSL and HSV (Hue, Saturation and Lightness/Value)

HSL and HSV (Hue, Saturation and Lightness/Value)

HSL and HSV are used in color pickers and sometimes to define gradients for data visualization. The popular GIS program ArcGIS historically applied customizable HSV-based gradients to numerical geographical data. HSL or HSV is often more convenient than RGB. The CSS 3 specification allows web authors to specify colors for their pages directly with HSL coordinates.

http://en.wikipedia.org/wiki/HSL_and_HSV describes the difference between HSL and HSV.

 

Note that HSB (brightness) is not the same as HSL, but is the same as HSV. Curiously, the Microsoft Office HSL color picker labels L “Lum” (luminosity), but appears to be the same as lightness.

 

The blue icons are displayed in grayscale by setting the saturation to zero using CSS.

 

BTW, CSS also offers hsla and rgba, which add the alpha channel to control opacity/transparency.